I. ˈflat ə n verb
( flattened ; flattened ; flattening -t( ə )niŋ ; flattens )
Etymology: flat (I) + -en
transitive verb
1. : to reduce to an even or more nearly even surface : make flat : level , smooth
flatten the seams with a steam iron
time flattens the mountains
2.
a. : to throw down : bring to the ground : prostrate
the hurricane flattened the forest
b. : depress , deject , dispirit
was flattened by grief
c. : to completely overwhelm
the senator flattened his opposition
as
(1) : to ruin financially
the depression flattened many young or small businesses
(2) slang : to knock out
the boxer was flattened in the seventh round
sometimes : to defeat decisively in any contest
(3) : to kill or destroy by or as if by crushing
the car flattened the farmer's hen
(4) : to make (as oneself) helplessly drunk
3. archaic : to make vapid or insipid
4.
a. : to make (as paint) lusterless
b. : to cover (a surface) with a priming coat or a coat of flat paint
5. Britain : flat 4
6. : to adjust (a sail) by hauling in the aftermost clew to help turn a sailboat — often used with in
intransitive verb
1. : to become flat or flatter: as
a. : to become dull, savorless, or lacking in spirit
b. : to get, move, or extend in or into a flat position or form — often used with out
hills flattening into coastal plains
the ruts flattened out under the pressure of wheels
c. : to become uniform or stabilized often at a new higher or lower level — usually used with out
prices are expected to flatten out after the holiday buying
performance tended to flatten out after an initial period of improvement
d.
(1) : to manipulate an airplane so as to bring its longitudinal axis parallel with the ground (as after a climb or a dive) — used with out
(2) of an airplane : to assume such a position — used with out
2. : to extend oneself in making an effort
the horses flattened into their collars
rose refreshed and flattened to the task of grubbing roots
II. transitive verb
: to stabilize especially at a lower level
the economic boom will flatten interest rates